Experimental study of the influence of proteolytic enzymes on the hydrolysis of protein substrates

1977 ◽  
Vol 11 (4) ◽  
pp. 447-451
Author(s):  
M. S. Son'kin ◽  
G. E. Grinberg ◽  
G. A. Mikhailets
Keyword(s):  
Experimental Study ◽  
Proteolytic Enzymes ◽  
Protein Substrates ◽  
Hydrolysis Of

scholarly journals Hydrolysis of14C-labelled proteins by rumen micro-organisms and by proteolytic enzymes prepared from rumen bacteria

1983 ◽  
Vol 50 (2) ◽  
pp. 345-355 ◽  
Author(s):  
R. J. Wallace
Keyword(s):  
Proteolytic Enzymes ◽  
Rumen Fluid ◽  
Performic Acid ◽  
Cross Linking ◽  
Acid Oxidation ◽  
Rumen Bacteria ◽  
Rate Of Hydrolysis ◽  
Micro Organisms ◽  
Hydrolysis Of

1. Proteins were labelled with14C in a limited reductive methylation using [14C]formaldehyde and sodium borohydride.2. The rate of hydrolysis of purified proteins was little (< 10%) affected by methylation and the14C-labelled digestion products were not incorporated into microbial protein during a 5 h incubation with rumen fluid in vitro. It was therefore concluded that proteins labelled with14C in this way are valid substrates for study with rumen micro-organisms.3. The patterns of digestion of14C-labelled fish meal, linseed meal and groundnut-protein meal by rumen micro-organisms in vitro were similar to those found in vivo.4. The rates of hydrolysis of a number of14C-labelled proteins, including glycoprotein II and lectin from kidney beans (Phaseolus vulgaris), were determined with mixed rumen micro-organisms and with proteases extracted from rumen bacteria. Different soluble proteins were digested at quite different rates, with casein being most readily hydrolysed.5. Proteins modified by performic acid oxidation, by cross-linking using 1,6-di-iso-cyanatohexane or by diazotization were labelled with14C. Performic acid treatment generally increased the susceptibility of proteins to digestion, so that the rates of hydrolysis of performic acid-treated proteins were more comparable than those of the unmodified proteins. Cross-linking resulted in a decreased rate of hydrolysis except with the insoluble proteins, hide powder azure and elastin congo red. Diazotization had little effect on the rate of hydrolysis of lactoglobulin and albumin, but inhibited casein hydrolysis and stimulated the breakdown of γ-globulin.

scholarly journals Redox-Mediated Post-Translational Modifications of Proteolytic Enzymes and Their Role in Protease Functioning

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 650
Author(s):  
Anastasiia I. Petushkova ◽  
Andrey A. Zamyatnin
Keyword(s):  
Redox Regulation ◽  
Proteolytic Enzymes ◽  
Post Translational Modifications ◽  
Regulated Cell Death ◽  
Age Related ◽  
Living Organisms ◽  
Dose Dependent ◽  
Hydrolysis Of ◽  
Flexible Dose ◽  
Dependent Mechanism

Proteolytic enzymes play a crucial role in metabolic processes, providing the cell with amino acids through the hydrolysis of multiple endogenous and exogenous proteins. In addition to this function, proteases are involved in numerous protein cascades to maintain cellular and extracellular homeostasis. The redox regulation of proteolysis provides a flexible dose-dependent mechanism for proteolytic activity control. The excessive reactive oxygen species (ROS) and reactive nitrogen species (RNS) in living organisms indicate pathological conditions, so redox-sensitive proteases can swiftly induce pro-survival responses or regulated cell death (RCD). At the same time, severe protein oxidation can lead to the dysregulation of proteolysis, which induces either protein aggregation or superfluous protein hydrolysis. Therefore, oxidative stress contributes to the onset of age-related dysfunction. In the present review, we consider the post-translational modifications (PTMs) of proteolytic enzymes and their impact on homeostasis.

THE PROTEOLYTIC ENZYMES OF MICROORGANISMS: III. SOME CHARACTERISTICS OF EXTRACELLULAR PROTEASES PRODUCED IN SUBMERGED CULTURE

1950 ◽  
Vol 28c (6) ◽  
pp. 600-612 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Low Temperatures ◽  
Free Amino ◽  
Submerged Culture ◽  
Culture Medium ◽  
Proteolytic Enzymes ◽  
Amino Groups ◽  
Extracellular Proteases ◽  
Egg Albumin ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

Some of the general characteristics of the proteases liberated into the culture medium by molds and actinomycetes grown in submerged culture have been studied. Species of Alternaria, Streptomyces, Mortierella, and Gliocladium were used. The enzymes resemble trypsin in that they are most active at a pH slightly above 7 and are inhibited by a preparation of egg albumin. They are stable at low temperatures but suffer marked losses in activity when stored for 16 hr. above 40 °C. The most rapid hydrolysis of gelatin occurs at temperatures between 40 °C. and 50 °C. The enzymes from different organisms show definite differences with respect to their ability to attack different proteins, gelatin and casein being in general the most readily digested. The protease systems from different organisms also vary with respect to the extent to which they can digest gelatin; some enzymes are able to release about three times as many amino groups from gelatin as others. The limit of the hydrolysis is not dependent upon substrate concentration but is slightly affected by the concentration of enzyme. The enzymes were effective in liberating free amino acids from gelatin.

SUSCEPTIBILITY OF PROTEINS USED IN CALF MILK REPLACERS TO HYDROLYSIS BY VARIOUS PROTEOLYTIC ENZYMES

1980 ◽  
Vol 60 (4) ◽  
pp. 907-914 ◽  
Author(s):  
K. J. JENKINS ◽  
S. MAHADEVAN ◽  
D. B. EMMONS
Keyword(s):  
Trichloroacetic Acid ◽  
Proteolytic Enzymes ◽  
Milk Proteins ◽  
In Vitro Study ◽  
Enzyme Treatment ◽  
Protein Hydrolysis ◽  
Protein Substrates ◽  
Optimum Ph ◽  
Milk Replacers

An in vitro study was conducted to assess the hydrolytic susceptibility of various milk and non-milk proteins (soybean, rapeseed, fish) used in calf milk replacers to endogenous and commercial proteolytic enzymes. Extent of protein hydrolysis (%) was calculated from the reduced amount of protein precipitated by 10% trichloroacetic acid following enzyme treatment. All of the enzymes tested hydrolyzed the milk proteins more extensively than the non-milk proteins both at their optimum pH, and at the pH (6.1) of calf abomasal contents immediately after feeding. At both optimum pH and pH 6.1, the highest average hydrolysis value for all protein substrates was obtained with pronase followed by papain, trypsin, pancreatin, chymotrypsin, Mucor miehei rennet andchymosin (calf rennet). All substrates were hydrolyzed extensively by pepsin at pH 2.0 but, as expected, very little hydrolysis occurred with this enzyme atpH6.1.

scholarly journals Input of Protein to Lake Water Microcosms Affects Expression of Proteolytic Enzymes and the Dynamics ofPseudomonas spp

2001 ◽  
Vol 67 (11) ◽  
pp. 4955-4962 ◽  
Author(s):  
Jakob Worm ◽  
Ole Nybroe
Keyword(s):  
Population Structure ◽  
Lake Water ◽  
Leucine Aminopeptidase ◽  
Proteolytic Enzymes ◽  
Extracellular Enzyme ◽  
Bacterial Consortium ◽  
Proteinase Activity ◽  
Aminopeptidase Activity ◽  
Growth Media ◽  
Hydrolysis Of

ABSTRACT The objective of this study was to determine how an input of protein to lake water affects expression of a proteolytic potential and influences the abundance and composition of a specific group of bacteria. Pseudomonas spp. were chosen as a target group that can be recovered on selective growth media and contain both proteolytic and nonproteolytic strains. Amendment with 2 mg of casein per liter increased total proteinase activity (hydrolysis of [3H]casein) by 74%, leucine-aminopeptidase activity (hydrolysis of leucine-methyl-coumarinylamide) by 133%, bacterial abundance by 44%, and phytoplankton biomass (chlorophylla) by 39%. The casein amendment also increased the abundance of culturable Pseudomonas spp. by fivefold relative to control microcosms but did not select for proteolytic isolates. Soluble proteins immunochemically related to thePseudomonas fluorescens alkaline proteinase, AprX, were detected in amended microcosms but not in the controls. The expression of this class of proteinase was confirmed exclusively for proteolyticPseudomonas isolates from the microcosms. The population structure of Pseudomonas isolates was determined from genomic fingerprints generated by universally primed PCR, and the analysis indicated that casein amendment led to only minor shifts in population structure. The appearance of AprX-like proteinases in the lake water might thus reflect a general induction of enzyme expression rather than pronounced shifts in the Pseudomonaspopulation structure. The limited effect of casein amendment onPseudomonas population structure might be due to the availability of casein hydrolysates to bacteria independent of their proteinase expression. In the lake water, 44% of the total proteinase activity was recovered in 0.22-μm-pore-size filtrates and thus without a direct association with the bacteria providing the extracellular enzyme activity. Since all Pseudomonasisolates expressed leucine-aminopeptidase in pure culture, proteolytic as well as nonproteolytic pseudomonads were likely members of the bacterial consortium that metabolized protein in the lake water.

Influence of some commercial proteases and enzymatic associations on the hydrolytic solubilization of deboned poultry meat proteins Influencia de algunas proteasas comerciales y preparados enzimáticos en la solubilización hidrolitica de las proteínas de la carne de pollo separada mecánicamente

2000 ◽  
Vol 6 (4) ◽  
pp. 301-306 ◽  
Author(s):  
L.H. de Barros Soares ◽  
D. Ney Marques ◽  
P. Melchionna Albuquerque ◽  
M.A. Záchia Ayub
Keyword(s):  
Soluble Protein ◽  
Proteolytic Enzymes ◽  
Poultry Meat ◽  
Initial Amount ◽  
Maximum Value ◽  
Initial Ph ◽  
Basic Source ◽  
Proteolytic Activities ◽  
Fungal Protease ◽  
Hydrolysis Of

Mechanically deboned poultry meat (MDPM) was used as a basic source of protein to assess the efficiency of seven proteolytic enzymes and some enzymatic associations over the hydrolysis of that protein. As a main parameter, the evolution of protein solubilization during 4 h of proteolysis was evaluated. The enzymes alcalase, esperase, flavourzyme, fungal protease, HT-proteolytic, papain, proteopex, and combinations of alcalase + flavourzyme, esperase + flavourzyme, HT-proteolytic + flavourzyme, and proteopex + flavourzyme were applied at concentrations of 0.60% and 1.20% of commercial product as a function of total protein. The initial pH was adjusted to 7.0 or 8.0 and the temperature was maintained at 50 °C or 60 °C according to optimal conditions for each enzyme. The proteolytic activities of the enzymes were also compared with azocasein. The hydrolysis index (HI), i.e., the rate between the maximum value and the initial amount of soluble protein was formulated to allow the comparison among treatments. Results showed that the temperature did not influence the proteolysis in the tested model. The association of alcalase + flavourzyme was shown to be more efficient than all other treatments, obtaining more than 70% of soluble protein. Fungal protease pre sented the lowest results.

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